An electric iron is an indispensable tool for electronic manufacture and electrical maintenance, and its main usage is to solder elements and components and wires. It is an essential device in the process of circuit reconstruction. The electric iron will produce smog in the soldering process, in which, the main components of rosin in a solder tin wire are abietic acid anhydride, p-Coumaric Acid and resin hydrocarbons, and when the temperature reaches 250 degrees, a part of the oxides can be decomposed into carbon dioxide, sulfur dioxide, acetaldehyde, rosin acid, isocyanate, hydrocarbons, and the like. The smog has toxicity, and will seriously endanger people's health.